In Ti-Slack someone mentioned, that there could be problems with push under Oreo: missing NotificationChannel. It is related to this SO thread:
https://stackoverflow.com/questions/45711925/failed-to-post-notification-on-channel-null-target-api-is-26
Since I don't have an Oreo phone yet I can't prove this but it something that should be on the roadmap if the problem exists in Ti.Goosh too